1. Field of the Invention
The present invention relates to an improved means for lifting and rigging pipe flanges into position for bolting and welding during installation of a flange onto a pipe end. More specifically, the present invention pertains to a device for lifting medium to large pipe blind flanges into position for installation in a way that improves worker safety. The present invention eliminates the need to weld a lifting eye to the flange, saving time and resources and reducing the overall cost of installation of the flange.
2. Description of the Prior Art
Many industries utilize piping systems to facilitate daily operations. For example, oil refineries, gas companies and sewage treatment facilities need to pump and store large volumes of gases and/or liquids. The transport and storage systems for these products are large and are designed for durability and safety, as a leak in one of these piping systems could be extremely hazardous. Typically, piping systems are welded together at various junctions and joints to prevent against leaks. Piping systems may comprise an array of individual components and assemblies. The present invention pertains specifically to pipe blind flange fittings, wherein its design is specifically suited therefor. These fittings are very heavy components that require specific techniques and safety precautions when installing. Their sheer size and weight necessitates the use of a mechanical lifting device, such as a crane or mechanical hoist, during their lifting and rigging into place during installation.
Blind flanges are flat, disk-like covers that affix over the ends of open pipes. They are often difficult to manipulate because of their weight and are challenging to lift and position because of their shape. A traditional procedure for lifting a flange involves welding a lifting eye onto the flange. The purpose of the lifting eye is to serve as a lift point for a crane hoist or other lifting apparatus, which is used to pick up the flange and suspend it while workers secure it to the pipe end assembly. The process is expensive and time consuming, as a worker must weld the lifting eye to the flange and then remove the lifting eye once the flange has been installed in the desired location. Another traditional procedure for lifting a flange involves inserting a chain through an eye of the flange and then using the chain to lift the flange. This method is highly hazardous to worker safety because any link of the chain could break and the flange could fall to the ground. There methods further do not provide the level of stability necessary for safe installation, as a chain or single lifting eye does not guarantee the device will not rotate while being positioned. This introduces a pinching risk for workers operating near the suspended flange and the pipe end, whereby clothing and limbs may be compressed therebetween if the flange is not statically supported. Worker safety and adequate precautions are paramount in such work environments and around construction sites, as accidents can lead to considerable injury to those involved.
There are many specialized devices that can facilitate the lifting of heavy industrial assembly components. For example, U.S. Pat. No. 4,530,536 to Williams describes a set of lifting tongs for use in conjunction with a crane for lifting I-beams. The device is designed for use by a single individual. The tongs are opened and closed by the operation of a pneumatic piston at the upper end of the set of tongs. A set of jaws exists at the lower ends of the tongs having a groove cut into the interior face of each jaw. The grooves are specifically designed to catch the edges of the top flange of an I-beam. A crane operator lowers the lifting tongs device around the sides of the beam that is to be lifted. The crane operator then operates the closing mechanism of the tongs. As the tongs close, the jaws come together to secure against the upper flange of the beam. The jaws are designed so that as the jaws are closing, if the crane operator slowly lifts the device with the crane hoist, the jaws catch the edges of the top flange of the beam within the jaw grooves.
The Williams device is particularly designed for the purpose of lifting I-beams. While the Williams device serves an important function by lifting such beams, the device could not be used for lifting blind flanges. The jaw and groove mechanism employed by the Williams device for catching the top edge flanges of an I-beam could not be used to grip the edges of a blind flange or support a pair of lifting bolts attached thereto, since the diameter of a blind flange is very likely to exceed the span of the top edge flanges of an I-beam and the tongs are not adapted to support the two bolts in a secure and stable manner.
U.S. Pat. No. 5,065,984 to Hake describes a clamp assembly device for lifting pins out of concrete forms. When concrete is poured, the outer edges of what is poured must be shaped into the desired form. A concrete form is typically a metal frame that is made from smaller segments of the form combined together to make the overall form of the concrete slab to be laid. The smaller portions of the frame fit together like puzzle pieces—connected to one another and held together via pins. The device attaches to a lifting mechanism, which can be a piece of industrial equipment that allows for an upward lifting element that facilitates lift needed when using the disclosed device. The lifting mechanism is important when using the Hake device properly as the pins must be removed from the concrete forms by pulling directly upward. Pulling the pins any direction other than vertically will damage the pin, the concrete form, or both. While suited for its particular requirement, the Hake device is limited to lifting concrete form pins. The present invention provides a lifting mechanism for use with a lifting mechanism, such as a crane or hoist, and is particularly suited for lifting pipe flanges into position for attachment onto a large pipe assembly or pipe end.
U.S. Pat. No. 5,344,207 to Grimm describes an apparatus for lifting tires that is used in conjunction with a lifting device, such as a crane. The device comprises two members for gripping a tire and a means for connecting to a crane. The first member is stationary, while the second member is movable. The second member has two positions: a tire lifting position and a tire non-lifting position. To use the device, a tire is placed between the two members when the second member of the device is in the non-lifting position. Once the tire is in properly placed in the device, the second member is moved by a user to the tire lifting position and locks into place so that the tire is gripped by the two members of the device.
Similar to the Grimm device is U.S. Pat. No. 5,064,334 to Cooley, wherein an apparatus for lifting large tractor tires is disclosed. The size of tractor tires makes them difficult to maneuver without the assistance of a lifting device. The Cooley device aims to lift and move tractor tires easily. When a tractor tire is standing upright on the tread, the Cooley device attaches to the tire by an attachment means. The tire attachment means connects to a boom, which is raised and lowered by a hand jack. The boom connects to a base and the boom is also capable of being pivotally rotatable to facilitate moving of the tractor tire from one point to another. One embodiment of the tire attachment means is a square-shaped clamp. The arms of the clamp extend around the sides of the tractor tire with the ends of the clamp arms wrapping under the rim of the tire so that when the clamp is closed around the tire, the tire is caught in the clamp. The boom can then be lifted, lifting the attached tractor tire with it by operating the hand jack.
Both the Grimm and Cooley devices are specifically suited for lifting tires. Each device employs a clamping mechanism is designed to grip, lift and suspend a tire. The clamping mechanisms of the Grimm and Cooley devices do not support the tire from below its structure in any way. The clamps merely pinch under the tire carcass such that the clamps encircle the sidewall and enter through the wheel opening. While it is unlikely, if the clamping mechanism of either the Grimm or Cooley devices were to fail, the tire would release or drop from the grip of the device. Such an accident could harm an individual or damage property. Not only is the present invention used for lifting blind flanges—and not tires—the present invention improves user safety in the event that the device where to fail. The claws of the present invention are designed to catch under a minimum or two lifting bolts inserted through eyes in a blind flange. Upstanding ends of both claws further prevent the flange from sliding from and end of the device. Since the present invention further employs the use of two claws and requires the claws catch a minimum of two lifting bolts during use, the safety redundancies incorporated into the present invention improve the overall safety of the device in operation should either one of the claws of the device, or one of the lifting bolts, fail.
U.S. Pat. No. 5,842,729 to Bunn describes a device for lifting large sections of heavy pipe. The device comprises a pair of lifting tongs that attach to a crane hoist or other lifting means. The tongs have two ends and are connected to each other at a pivot point. The bottom end of each tong curves inward towards the center of the tongs such that as the tongs close, they wrap around the cylindrical shape of the pipe cross section being moved. The top end of each tong connects to the other by a highly durable cable. The cable is looped through a lifting means, such as a crane hoist or a forklift. As the crane hoist or forklift rises, it pulls upward on the cable connecting the two top ends of the tongs, causing the top ends of the tongs to move towards one another. The tongs are positioned in a scissor configuration, wherein the cable action on the tongs compresses the working ends of the tongs around a pipe section. As the top ends of the tongs move towards each other, the bottom ends also compress towards each other, wrapping around the section of cylindrical piping. These tongs are not suited for adequately lifting or supporting lift bolts of a blind flange. The scissor action provides lateral compression but inadequate support under the flange bolts, which is necessary for safely and securely lifting a blind flange. The present invention provides a means to support a blind flange and lift bolts thereof in a secure and safety redundant manner.
The present invention provides a pair of rotatable, L-shaped claws that are rotatably connected and offset from one another via a common pin attachment. The claws are adapted to be placed under a pair of lift bolts inserted through fastener locations on a blind flange. The claws attached on either side of the flange and provide a support means that resists slippage or dislodgement of the claws while lifting. Spacers along the pins provide the offset between claws, and further prevent the claws from binding or creating pinch points along the pin. It is therefore submitted that the present invention substantially diverges in design elements from the prior art, and consequently it is clear that there is a need in the art for an improvement to existing flange lifting devices. In this regard, the instant invention substantially fulfills these needs.